481 FXUS66 KPQR 202110 AFDPQR Area Forecast Discussion National Weather Service Portland Oregon 209 PM PDT Thu Oct 20 2016 .SYNOPSIS...A rather moist and fairly active cold front will continue to move through southwest Washington and northwest Oregon for periods of rain and some coastal breezes this afternoon, then linger over eastern Lane and Linn counties tonight into Friday before dissipating during the day Friday as weak high pressure builds into the forecast area. The next disturbance will bring some showers onshore Friday afternoon and evening, with drier weather possible Saturday. The next cold front will move onshore Saturday night ahead of a broad, cool upper low from Alaska that will set up off the Pacific NW coast Sunday and continue near the coast and produce unsettled weather into at least the first half of next week. && .SHORT TERM...Tonight through Sunday...A cold front was moving through the Portland area around noon to 1 pm this afternoon. The front will continue moving south and east through northwest Oregon this afternoon as a wave evident on IR satellite imagery along the front moves through the area. The models continue to say the front will linger tonight into Saturday in eastern Lane and Linn counties with some steadier precipitation that gradually decreases, but areas to the north and west will be drying out with perhaps some patchy fog developing later tonight and Friday morning. There are not many showers immediately behind the front so shower coverage tonight and early Friday will be on the sparse side. The main area of showers and instability are located well to our northeast near 50N/140W and are associated with the parent low to our current front. These showers approach our forecast area Friday, perhaps not spreading onshore until Friday afternoon and Friday evening. The models indicate some instability over the coastal waters and along the coast and have some thunder mentioned there, but this is not indicated for inland areas at this point. The next disturbance looks to spread a front toward the coast by late Saturday and especially Saturday night, but inland areas are looking relatively dry Saturday after some local areas of morning fog. The front will likely still be over southwest Washington and northwest Oregon on Sunday and produce some more showers before weakening. The parent low will be setting up off the coast by fairly early Sunday, and will continue to produce unsettled weather into at least early next week. Tolleson .LONG TERM...(Sunday night through Thursday)...Rainy pattern continues, though no big storms on the horizon. As normally occurs in this type of pattern, there has been a significant change in the track of the Low that sets up off the coast of Washington and Oregon over the weekend. Now, the Low is expected to track north into Vancouver Island, which will keep snow levels higher than previously forecast for early next week. This Low isn't forecast to get deeper than 985 mb, and should remain well offshore, so not expecting it to get more than a little breezy along the Coast next week. With regard to rain next week, there will be a cold front that moves across the area on Monday, bringing another round of moderate rainfall across the area, with higher amounts expected in the Central Coast Range of Western Oregon, South Willamette Valley, and Central Oregon Cascades. On Tuesday, the occluded Low bends back and sends through a secondary front associated with the bent-back occlusion for a round of moderate showers. Broad troughing remains over the Northeast Pacific and Pacific Northwest, with precipitation continuing through midweek. Details become much less certain by Wednesday, though pattern suggests rain will continue through at least Thursday. -McCoy && .AVIATION...Cold front now extends from near KTTD to KSLE to just south of Florence. Front will slowly push farther east and south, but will stall tonight and weaken. Generally MVFR along and ahead of the front, with those conditions persisting tonight over good part of inland Lane county northward along the Cascade Foothills. Farther north and along the coast, clouds will continue breaking up through this evening, but will keep a few showers around. Clearing areas should be large enough to allow areas of fog and/or low clouds to form later tonight. KPDX AND APPROACHES...VFR with occasional brief MVFR cigs for rest of this afternoon, but clouds gradually breaking up after 00z. With wet ground and light winds, any clearing should allow areas of fog and/low clouds to form. Likely to get IFR conditions after 10z...and lasting into Fri am. Rockey. && .MARINE...Cold front now onshore in northwest Oregon, but still lies from Florence back to southwest over the Oregon coastal waters around Florence. Now much more benign conditions over the coastal waters, with winds under 15 kt and seas 7 to 8 ft through Fri afternoon. Broad area of low pressure remains over the Gulf of Alaska into early next week. This will maintain active storm track across the north Pac and into the Pac NW. End result is a series of fronts will continue to move across the region. Next will be a weak front late Fri, with a somewhat stronger front arriving late Sat and Sat night. Some potential that that Sat system will bring a round of low-end southerly gales, with seas back at 12 to 15 ft. Another front arrives later Sun. Rockey. && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...Small Craft Advisory for Rough Columbia River Bar from 6 PM to 11 PM this evening. && $$ Interact with us via social media: www.facebook.com/NWSPortland www.twitter.com/NWSPortland This discussion is for Northwest Oregon and Southwest Washington from the Cascade crest to 60 nautical miles offshore. The area is commonly referred to as the forecast area.
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